A user interface facilitates the interaction between a computer and computer user by enhancing the user's ability to utilize application programs. The traditional interface between a human user and a typical personal computer is implemented with graphical displays and is generally referred to as a graphical user interface (GUI). Input to the computer or particular application program is accomplished through the presentation of graphical information on the computer screen and through the use of a keyboard and/or mouse, trackball or other similar implements. Many systems employed for use in public areas utilize touch screen implementations whereby the user touches a designated area of a screen to effect the desired input. Airport electronic ticket check-in kiosks and rental car direction systems are examples of such systems. There are, however, many applications where the traditional user interface is less practical or efficient.
The traditional computer interface is not ideal for a number of applications. Providing stand-up presentations or other type of visual presentations to large audiences, is but one example. In this example, a presenter generally stands in front of the audience and provides a verbal dialog in conjunction with the visual presentation that is projected on a large display or screen. Manipulation of the presentation by the presenter is generally controlled through use of awkward remote controls, which frequently suffer from inconsistent and less precise operation, or require the cooperation of another individual. Traditional user interfaces require the user either to provide input via the keyboard or to exhibit a degree of skill and precision more difficult to implement with a remote control than a traditional mouse and keyboard. Other examples include control of video, audio, and display components of a media room. Switching between sources, advancing fast fast-forward, rewinding, changing chapters, changing volume, etc., can be very cumbersome in a professional studio as well as in the home. Similarly, traditional interfaces are not well suited for smaller, specialized electronic gadgets.
Additionally, people with motion impairment conditions find it very challenging to cope with traditional user interfaces and computer access systems. Such conditions include Cerebral Palsy, Muscular Dystrophy, Friedrich's Ataxia, and spinal injuries or disorders. These conditions and disorders are often accompanied by tremors, spasms, loss of coordination, restricted range of movement, reduced muscle strength, and other motion impairing symptoms.
Similar symptoms exist in the growing elderly segment of the population. As people age, their motor skills decline and impact the ability to perform many tasks. It is known that as people age, their cognitive, perceptual and motor skills decline, with negative effects in their ability to perform many tasks. The requirement to position a cursor, particularly with smaller graphical presentations, can often be a significant barrier for elderly or afflicted computer users. Computers can play an increasingly important role in helping older adults function well in society.
Graphical interfaces contribute to the ease of use of computers. WIMP (Window, Icon, Menu, Pointing device (or Pull-down menu)) interfaces allow fairly non-trivial operations to be performed with a few mouse motions and clicks. However, at the same time, this shift in the user interaction from a primarily text-oriented experience to a point-and-click experience has erected new barriers between people with disabilities and the computer. For example, for older adults, there is evidence that using the mouse can be quite challenging. There is extensive literature demonstrating that the ability to make small movements decreases with age. This decreased ability can have a major effect on the ability of older adults to use a pointing device on a computer. It has been shown that even experienced older computer users move a cursor much more slowly and less accurately than their younger counterparts. In addition, older adults seem to have increased difficulty (as compared to younger users) when targets become smaller. For older computer users, positioning a cursor can be a severe limitation.
One solution to the problem of decreased ability to position the cursor with a mouse is to simply increase the size of the targets in computer displays, which can often be counter-productive since less information is being displayed, requiring more navigation. Another approach is to constrain the movement of the mouse to follow on-screen objects, as with sticky icons or solid borders that do not allow cursors to overshoot the target. There is evidence that performance with area cursors (possibly translucent) is better than performance with regular cursors for some target acquisition tasks.
One method to facilitate computer access for users with motion impairment conditions and for applications, in which the traditional user interfaces are cumbersome, is through use of perceptual user interfaces. Perceptual user interfaces utilize alternate sensing modalities, such as the capability of sensing physical gestures of the user, to replace or complement traditional input devices such as the mouse and keyboard. Perceptual user interfaces promise modes of fluid computer-human interaction that complement and/or replace the mouse and keyboard, particularly in non-desktop applications such as control for a media room.
One study indicates that adding a simple gesture-based navigation facility to web browsers can significantly reduce the time taken to carry out one of the most common actions in computer use, i.e., using the “back” button (or function) to return to previously visited pages. Subjective ratings by users in experiments showed a strong preference for a “flick” system, where the users would flick the mouse left or right to go back or forward in the web browser.
In the simplest view, gestures play a symbolic communication role similar to speech, suggesting that for simple tasks gesture may enhance or replace speech recognition. Small gestures near the keyboard or mouse do not induce fatigue as quickly as sustained whole arm postures. Previous studies indicate that users find gesture-based systems highly desirable, but that users are also dissatisfied with the recognition accuracy of gesture recognizers. Furthermore, experimental results indicate that a user's difficulty with gestures is in part due to a lack of understanding of how gesture recognition works. The studies highlight the ability of users to learn and remember gestures as an important design consideration.
Even when a mouse and keyboard are available, users may find it attractive to manipulate often-used applications while away from the keyboard, in what can be called a “casual interface” or “lean-back” posture. Browsing e-mail over morning coffee might be accomplished by mapping simple gestures to “next message” and “delete message”.
Gestures may compensate for the limitations of the mouse when the display is several times larger than a typical display. In such a scenario, gestures can provide mechanisms to restore the ability to quickly reach any part of the display, where once a mouse was adequate with a small display. Similarly, in a multiple display scenario it is desirable to have a fast comfortable way to indicate a particular display. For example, the foreground object may be “bumped” to another display by gesturing in the direction of the target display.
However, examples of perceptual user interfaces to date are dependent on significant limiting assumptions. One type of perceptual user interface utilizes color models that make certain assumptions about the color of an object. Proper operation of the system is dependent on proper lighting conditions and can be negatively impacted when the system is moved from one location to another as a result of changes in lighting conditions, or simply when the lighting conditions change in the room. Factors that impact performance include sun light versus artificial light, florescent light versus incandescent light, direct illumination versus indirect illumination, and the like. Additionally, most attempts to develop perceptual user interfaces require the user to wear specialized devices such as gloves, headsets, or close-talk microphones. The use of such devices is generally found to be distracting and intrusive for the user.
Thus perceptual user interfaces have been slow to emerge. The reasons include heavy computational burdens, unreasonable calibration demands, required use of intrusive and distracting devices, and a general lack of robustness outside of specific laboratory conditions. For these and similar reasons, there has been little advancement in systems and methods for exploiting perceptual user interfaces. However, as the trend towards smaller, specialized electronic gadgets continues to grow, so does the need for alternate methods for interaction between the user and the electronic device. Many of these specialized devices are too small and the applications unsophisticated to utilize the traditional input keyboard and mouse devices. Examples of such devices include TabletPCs, Media center PCs, kiosks, hand held computers, home appliances, video games, and wall sized displays, along with many others. In these, and other applications, the perceptual user interface provides a significant advancement in computer control over traditional computer interaction modalities.
In light of these findings, what is needed is to standardize a small set of easily learned gestures, the semantics of which are determined by application context. A small set of very simple gestures may offer significant bits of functionality where they are needed most. For example, dismissing a notification window may be accomplished by a quick gesture to the one side or the other, as in shooing a fly. Another example is gestures for “next” and “back” functionality found in web browsers, presentation programs (e.g., PowerPoint™) and other applications. Note that in many cases the surface forms of these various gestures may remain the same throughout these examples, while the semantics of the gestures depends on the application at hand. Providing a small set of standard gestures eases problems users have in recalling how gestures are performed, and also allows for simpler and more robust signal processing and recognition processes.